.nav-bar {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 20px 0;
}

.nav-item {
    margin: 0 10px;
    position: relative;
    width: 7%;
    display: flex; /* 将按钮设置为flex布局 */
    justify-content: center; /* 水平居中按钮 */
    align-items: center; /* 垂直居中按钮 */
}

.nav-btn {
    background-color: transparent;
    border: none;
    cursor: pointer;
    font-size: 16px;
    color: #333;
    display: flex; /* 将按钮设置为flex布局 */
    justify-content: center; /* 水平居中按钮 */
    align-items: center; /* 垂直居中按钮 */
}

.nav-line {
    display: none;
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: #67e2b7;
}

.nav-btn:hover + .nav-line {
    display: block;
}